Development of adventitious roots (ARs) at the base of the shoot is an important adaptation of plants to waterlogging stress; however, its physiological mechanisms remain unclear. Here, we investigated the regulation of AR formation under waterlogged conditions by hormones and reactive oxygen species (ROS) in Cucumis sativus L., an agriculturally and economically important crop in China. We found that ethylene, auxin, and ROS accumulated in the waterlogged cucumber plants. On the other hand, application of the ethylene receptor inhibitor 1-methylcyclopropene (1-MCP), the auxin transport inhibitor 1-naphthylphthalamic acid (NPA), or the NADPH oxidase inhibitor diphenyleneiodonium (DPI) decreased the number of ARs induced by waterlogging. Auxin enhanced the expression of ethylene biosynthesis genes, which led to ethylene entrapment in waterlogged plants. Both ethylene and auxin induced the generation of ROS. Auxin-induced AR formation was inhibited by 1-MCP, although ethylene-induced AR formation was not inhibited by NPA. Both ethylene-and auxin-induced AR formation were counteracted by DPI.These results indicate that auxin-induced AR formation is dependent on ethylene, whereas ethylene-induced AR formation is independent of auxin. They also show that ROS signals mediate both ethylene-and auxin-induced AR formation in cucumber plants.

Calcium-dependent protein kinases (CDPKs) are multi-functional proteins that combine calcium-binding and signaling capabilities within a single gene product. Current studies have shown that the CDPKs regulate numerous growth and developmental processes and biotic and abiotic stress responses. Nonetheless, knowledge concerning the specific expression patterns and evolutionary history of the CDPK family in cucumber (Cucumis sativus L.) remains very limited. We, therefore, investigated the phylogenetic relationships and expression profiles of the 19 CDPK genes identified in the cucumber genome sequence, resolving them into four subfamilies based on a phylogenetic tree and gene structures. Tissue-specific expression profiles suggest that cucumber CDPK genes are involved in cucumber tissue development. An expression analysis based on qRT-PCR indicated that cucumber CDPK genes are extensively involved in abscisic acid, salt, cold, drought, heat, and waterlogging responses, possibly by different mechanisms. The fates of two paralogs after divergence were also investigated, suggesting subfunctionalization and neofunctionalization during evolution. These observations lay an important foundation for functional and evolutionary analyses of the CDPK gene family in cucurbitaceae species.

The authentication of olive oil and its adulteration with lower priced oils are still serious problems in the olive oil industry. In this study, a method based on the intensity ratio of the Raman spectroscopy vibration bands, especially on the intensity ratio of the cis ( ==C-H) and cis (C=C) bonds normalized by the band at 1441 cm(-1) (CH(2)), was established to authenticate genuine/fake olive oil. These intensity ratios of the vibration bands given in the form of a two-dimensional chart allow first the discrimination between the various grades of olive oil and the seed oils and then the detection of olive oil fraud by the line of y = 0.7, which is observed under most experiments and dot charts. This method can reliably distinguish the genuine olive oils from the olive oils containing 5% (volume percentage) or more of other edible oils, such as soybean oil, rapeseed oil, sunflower seed oil, or corn oil. Compared to the traditional principal component analysis method, this method is more intuitive, more precise, and easier to use. Moreover, this method also has the advantages of simplicity efficiency and has no need for sample preprocessing, being especially suitable for on-site testing in field applications.

High-density genetic map provides an essential framework for accurate and efficient genome assembly and QTL fine mapping. Construction of high-density genetic maps appears more feasible since the advent of next-generation sequencing (NGS), which eases SNP discovery and high-throughput genotyping of large population. In this research, a high-density genetic map of cucumber (Cucumis sativus L.) was successfully constructed across an F2 population by a recently developed Specific Length Amplified Fragment sequencing (SLAF-seq) method. In total, 18.69 GB of data containing 93,460,000 paired-end reads were obtained after preprocessing. The average sequencing depth was 44.92 in the D8 (female parent), 42.16 in the Jin5-508 (male parent), and 5.01 in each progeny. 79,092 high-quality SLAFs were detected, of which 6784 SLAFs were polymorphic, and 1892 of the polymorphic markers met the requirements for constructing genetic map. The genetic map spanned 845.87 cm with an average genetic distance of 0.45 cm. It is a reliable linkage map for fine mapping and molecular breeding of cucumber for its high marker density and well-ordered markers.

Melamine, a nitrogen-rich chemical, has recently caused enormous economic losses to the food industry due to the cases of milk products adulterated by melamine. This has led to an urgent need of rapid and reliable methods for detection of melamine in food. In this study, surface-enhanced Raman scattering (SERS) spectroscopy was used to detect melamine in liquid milk. The sample preparation with liquid milk is very easy; it has to be only diluted with double-distilled water followed by centrifugation. By using a silver colloid, at least a 10 5 -fold enhancement of the Raman signal was achieved for the measurement of melamine. The limit of detection by this method was 0.01 µg ml −1 for melamine standard samples. Based on the intensity of the Raman vibrational bands normalised to that of the band at 928 cm −1 (CH 2 ), an external standard method was employed for quantitative analysis. The linear regression square (R 2 ) of the curve was 0.9998; the limit of quantitation using this approach was 0.5 µg ml −1 of melamine in liquid milk; the relative standard deviation was ≤10%; and recoveries were from 93 to 109%. The test results for SERS were very precise and as good as those obtained by liquid chromatography/tandem mass spectrometry. The method was simple, fast(only needs about 3 min), cost effective, and sensitive for the detection of melamine in liquid milk samples. Therefore, it is more suitable for the field detection of melamine in liquid milk.